1. Field of the Invention
The present invention relates to an electron microscope plasma cleaner that has a triple plasma electrode and a multi gas injection nozzle, thus achieving the effective generation of plasma, and more particularly, to an electron microscope plasma cleaner that cleans the interior of a chamber of an electron microscope and the surface of a sample of the electron microscope with the radicals and ions produced by means of plasma, thus achieving the improvements in high resolution image observation and precision length measurement of the electrode microscope and the pattern distortion and damage of the image observed through the electrode microscope.
2. Background of the Related Art
An electron microscopes, which collects an electron beam and produces a focus thereon to observe and analyze the surface and interior of a sample, includes a scanning electron microscope (SEM), a critical dimension-scanning electron microscope (CD-SEM), a transmission electron microscope (TEM), dual beam (SEM+FIB (focused ion beam)), a nano prober and so on.
The electron microscope is a device that produces a high density electron current from an electron gun, collects an electron beam in an electron column, forms a focus thereon, radiates the electron beam onto a local observation point of a sample to be analyzed, produces and detects a signal, and magnifies (tens to millions of times) the image on the surface and interior of the sample.
With the development of nano technology, the electron microscope becomes necessary equipment for research, manufacturing process and quality management in all kinds of industrial fields like semiconductors, advanced materials, displays and so on.
On the other hand, cleaning organics and native oxide existing on the interior of a vacuum chamber of the electron microscope and the surface of a sample becomes a serious problem.
That is, the contamination caused by the organics on the vacuum chamber of the electron microscope and the surface of the sample gives bad interference in the observation of the image of the electron microscope, thus undesirably causing the contamination and deformation of the observed region and providing main interference in the spatial resolution like noise increment of the image.
The contamination on the vacuum chamber of the electron microscope is caused by the outgas from a photo resist as a main material of a semiconductor process and an organic material having high permittivity and weak bonding characteristics.
Further, the contamination of the vacuum chamber is caused by the contaminants of various structures (a sample stage, a sample holder and so on) of the vacuum chamber and the out-gas from grease.
Such organics have heavy mass and low motion energy, and accordingly, since most of organics are not pumped by means of a vacuum pump, they are absorbed/desorbed in the vacuum chamber and randomly move to collide against the beam incident thereon, thus being positively ionized. Further, the positive ions are deposited onto the area of the sample to which the electron beam is radiated having high negative charges therearound to form a black organic ion deposited film, which decreases the resolution of the image or deforming the observed pattern, thus making it hard to achieve accurate observation or fine measurement.
Further, the contamination of the organics on the surface of the sample is caused by various kinds of chemicals used for making the sample, residues reacting to the chemicals, water remaining after washing, and oil and water of a user′ body.
When the sample is kept in the air, further, native oxide is formed thereon to cause the surface of the sample to be contaminated.
If the contaminated sample is introduced into the sample chamber to observe the image of the electron microscope, the pattern distortion and the reduction of resolution of the observed image may become serious.
So as to solve the above-mentioned problems, accordingly, there is a definite need for the development of a new electron microscope plasma cleaner.